Scramble key management unit, scramble key management information transmitting unit, method for scramble key output management, scramble key management program, license information management unit, license management information transmitting unit, method for license information output management, and license information management program

Abstract

A low cost scramble key management apparatus which enables to manage a scramble key based on individual contract information and to ensure security in narrow band broadcasting. The scramble key management apparatus 7 includes an ECM decoding unit 75 for decoding an ECM in which a scramble key and individual contract information are encrypted. The individual contract information includes contract information indicating contract statuses of a plurality of content receivers 3, 3 , . . . which is arranged based on receiver IDs for identifying each of the content receivers 3 . The scramble key management apparatus 7 includes a contract information obtaining unit 76 b for obtaining the contract information of the content receiver 3 associated with the receiver ID from the individual contract information and a contract status determining unit 76 c for determining the contract status and outputting the scramble key to a content decoder 5 if the contract status is under contract.

What is claimed is: 
     
       1. A scramble key management apparatus which manages an output of a scramble key for decoding an encrypted content to a content decoder which receives and decodes the encrypted content, comprising:
 a scramble key management information decoding device which decodes scramble key management information in which the scramble key and individual authorization information are encrypted, the individual authorization information including authorization information for a plurality of the content decoders, wherein the authorization information for the plurality of the content decoders includes a sequence of bits, wherein each bit is associated with a single one of the plurality of content decoders and the bits are arranged in a numerical order of decoder IDs of the plurality of the content decoders to indicate presence or absence of authorization for each of the plurality of the content decoders to decode the encrypted content; 
 an authorization information obtaining device which obtains the authorization information for the content decoder of an output target from the individual authorization information decoded by the scramble key management information decoding device based on the decoder ID of the content decoder of the output target; and 
 an authorization status determining device which determines whether or not the content decoder is authorized to decode the encrypted content based on the authorization information obtained by the authorization information obtaining device, and outputs the scramble key to the content decoder of the output target if the content decoder is authorized to decode the encrypted content. 
 
     
     
       2. The scramble key management apparatus according to  claim 1 , wherein a plurality of content decoders which are transmission targets of the encrypted content is classified into a plurality of groups in advance, the authorization information of a plurality of the content decoders included in one of the plurality of groups is arranged in the individual authorization information, a group ID for identifying the one of the plurality of groups is included in the individual authorization information, and wherein
 the authorization information obtaining device obtains the authorization information based on the group ID and the decoder ID. 
 
     
     
       3. A scramble key management information transmitting apparatus which transmits to the scramble key management apparatus according to  claim 1  scramble key management information in which a scramble key for decoding an encrypted content and individual authorization information are encrypted, the individual authorization information including authorization information indicating a presence or absence of authorization to decode the encrypted content for each of a plurality of content decoders which receives and decodes the encrypted content, comprising:
 an individual authorization information generation device for generating individual authorization information in which the authorization information for a plurality of the content decoders which is input from outside is arranged based on a decoder ID which identifies the content decoder, and 
 a scramble key management information generation device for encrypting the individual authorization information generated by the individual authorization information generation device and the scramble key to generate the scramble key management information. 
 
     
     
       4. The scramble key management information transmitting apparatus according to  claim 3 , wherein the individual authorization information generation device generates the individual authorization information including a bit string in which the authorization information, each piece of which is one bit, is arranged. 
     
     
       5. The scramble key management information transmitting apparatus according to  claim 4 , wherein the individual authorization information generation device losslessly compresses the bit string. 
     
     
       6. A scramble key output management method for managing an output of a scramble key for decoding an encrypted content to a content decoder which decodes the encrypted content, the method comprising steps of:
 a scramble key management information decoding step performed by a computer to decode scramble key management information in which the scramble key and individual authorization information are encrypted, the individual authorization information including authorization information for a plurality of the content decoders, wherein the authorization information for the plurality of content decoders includes a sequence of bits, wherein each bit is associated with a single one of the plurality of content decoders and the bits are arranged in a numerical order of decoder IDs of the plurality of content decoders to indicate presence or absence of authorization for each of the plurality of the content decoders to decode the encrypted content; 
 an authorization information obtaining step for obtaining the authorization information for the content decoder of an output target from the individual authorization information decoded by the scramble key management information decoding device based on the decoder ID of the content decoder of the output target; 
 an authorization status determining step for determining whether or not the content decoder is authorized to decode the encrypted content based on the authorization information obtained by the authorization information obtaining unit; and 
 a key output step for outputting the scramble key to the content decoder of the output target if the content decoder is determined to be authorized to decode the encrypted content in the authorization status determining step. 
 
     
     
       7. A computer readable non-transitory recording medium which stores a scramble key management program which causes a computer managing an output of a scramble key for decoding an encrypted content to a content decoder which receives and decodes the encrypted content to function as:
 a scramble key management information decoding means for decoding scramble key management information in which the scramble key and individual authorization information are encrypted, the individual authorization information including authorization information for a plurality of the content decoders, wherein the authorization information for the plurality of the content decoders includes a sequence of bits, wherein each bit is associated with a single one of the plurality of content decoders and the bits are arranged in a numerical order of decoder IDs of the plurality of the content decoders to indicate presence or absence of authorization for each of the plurality of the content decoders to decode the encrypted content; 
 an authorization information obtaining means for obtaining the authorization information for the content decoder of an output target from the individual authorization information decoded by the scramble key management information decoding means based on the decoder ID of the content decoder of the output target; and 
 an authorization status determining means for determining whether or not the content decoder is authorized to decode the encrypted content based on the authorization information obtained by the authorization information obtaining means and outputting the scramble key to the content decoder of the output target if the content decoder is authorized to decode the encrypted content. 
 
     
     
       8. A license information management apparatus for managing an output of license information for displaying a content to a content obtaining device which receives and displays the content, comprising:
 a license management information decoding device which decodes license management information in which individual authorization information is encrypted, the individual authorization information including authorization information for a plurality of the content obtaining devices, wherein the authorization information for the plurality of the content obtaining devices includes a sequence of bits wherein each bit is associated with a single one of the plurality of the content obtaining devices and the bits are arranged in a numerical order of content obtaining device IDs of the plurality of the content obtaining devices to indicate presence or absence of authorization for each of the plurality of the content obtaining devices; 
 an authorization information obtaining device which obtains the authorization information for the content obtaining device of an output target from the individual authorization information decoded by the license management information decoding device based on the receiver ID of the content obtaining device of the output target; and 
 an authorization status determining device which determines whether or not the content obtaining device is authorized to display the content based on the authorization information obtained by the authorization information obtaining device, and outputs the license information to the content obtaining device of the output target if the content obtaining device is authorized to display the content. 
 
     
     
       9. The license information management apparatus according to  claim 8 , wherein the content obtaining device is a content decoder which decodes an encrypted content which is encrypted with a scramble key with the scramble key, and the license information is the scramble key. 
     
     
       10. License information management apparatus which manages an output of license information for displaying a content to a content obtaining device which receives and displays the content, comprising:
 a license management information decoding device which decodes license management information in which individual authorization information is encrypted, the individual authorization information including authorization information for a plurality of the content obtaining devices, wherein the authorization information for the plurality of the content obtaining devices includes a sequence of bits wherein each bit is associated with a single one of the plurality of the content obtaining devices and the bits are arranged in a numerical order of content obtaining device IDs of the plurality of content obtaining devices to indicate presence or absence of authorization for each of the plurality of the content obtaining devices to display the content; 
 an authorization information obtaining device which obtains the authorization information for the content obtaining device of an output target from the individual authorization information decoded by the license management information decoding device based on the first receiver ID of the content obtaining device of the output target; 
 a lock control information obtaining device that obtains lock control information associated with a second receiver ID for controlling a lock status which is either a status where the output of the license information to the content obtaining device is allowed or a status where the output of the license information to the content obtaining device is prohibited, the second receiver ID identifying a larger number of the content obtaining devices than the first receiver ID; 
 a lock control device that controls the lock status based on the lock control information; and 
 an authorization status determining device which determines whether or not the content obtaining device is authorized to display the content based on the authorization information obtained by the authorization information obtaining unit, and outputting the license information to the content obtaining device of the output target if the content obtaining device is authorized to display the content and the lock status is the status where the output of the license information is allowed. 
 
     
     
       11. The license information management apparatus according to  claim 10 , wherein a plurality of content obtaining devices which are transmission targets of the content is classified into a plurality of groups in advance, the authorization information of a plurality of the content obtaining devices included in one of the plurality of groups is arranged in the individual authorization information, a group ID for identifying the one of the plurality of groups is included in the individual authorization information, and wherein the authorization information obtaining device obtains the authorization information based on the group ID and the first receiver ID. 
     
     
       12. The license information management apparatus according to  claim 10 , further comprising a first receiver ID storage device for storing the first receiver ID, wherein if the lock control information includes information for controlling the lock status to the status where the output of the license information is allowed the lock control information includes at least a first receiver ID and the license information management apparatus updates the first receiver ID stored in the first receiver ID storage device to the first receiver ID included in the lock control information. 
     
     
       13. The license information management apparatus according to  claim 11 , further comprising a first receiver ID storage device for storing the first receiver ID and the group ID, wherein if the lock control information includes information for controlling the lock status to the status where the output of the license information is allowed the lock control information includes at least a first receiver ID and a group ID, and the license information management apparatus updates the first receiver ID and the group ID stored in the first receiver ID storage device to the first receiver ID and the group ID included in the lock control information, respectively. 
     
     
       14. The license information management apparatus according to  claim 10 , further comprising a lock determining device for determining whether or not to change the lock status to the status where the output of the license information is prohibited based on predetermined date information and a present date, wherein the lock control device controls the lock status based on the lock control information and a determination result of the lock determining unit. 
     
     
       15. The license information management apparatus according to  claim 10 , wherein the first receiver ID is assigned a different ID by each channel in which the content obtaining device receives the content, the different ID being associated with a channel ID for identifying a channel, and wherein the lock control device controls the lock status by the each channel. 
     
     
       16. The license information management apparatus according to  claim 14 , wherein the first receiver ID is assigned a different ID by each channel in which the content obtaining device receives the content, the different ID being associated with a channel ID for identifying a channel, and wherein the lock determining device determines whether or not to change the lock status to the status where the output of the scramble key is prohibited based on the predetermined date information associated with the channel and the present date, and wherein the lock control device controls the lock status by the each channel based on the lock control information and a determination result of the lock determining unit. 
     
     
       17. The license information management apparatus according to  claim 10 , wherein the content obtaining device is a content decoder for decoding an encrypted content which is encrypted with a scramble key with the scramble key, and the license information is the scramble key. 
     
     
       18. A license management information transmitting apparatus for transmitting to the license information management apparatus according to  claim 10  license management information in which individual authorization information is encrypted, the individual authorization information including authorization information indicating a presence or absence of authorization for each of a plurality of the content decoders which receives and displays a content to display the content, comprising:
 an individual authorization information generation device for generating the individual authorization information in which authorization information input from outside for the plurality of the content obtaining devices is arranged based on a first receiver ID for identifying each of the content obtaining devices; 
 a license management information generation device for encrypting the individual authorization information generated by the individual authorization information generation device to generate license management information; and 
 a lock control information generation device for generating lock control information which is associated with a second receiver ID and changes a lock status of the license information management apparatus, the second receiver ID identifying a larger number of the content obtaining devices than the first receiver ID. 
 
     
     
       19. A license information output management method for managing an output of license information for displaying a content to a content obtaining device for receiving and displaying the content, comprising steps of:
 a license management information decoding step performed by a computer to decode license management information in which individual authorization information is encrypted, the individual authorization information including authorization information for a plurality of the content obtaining devices, wherein the authorization information for the plurality of the content obtaining devices includes a sequence of bits, wherein each bit is associated with a single one of the plurality of the content obtaining devices and the bits are arranged in a numerical order of content obtaining device IDs of the plurality of the content obtaining devices to indicate presence or absence of authorization for each of the plurality of the content obtaining devices to display the content; 
 an authorization information obtaining step for obtaining the authorization information for the content obtaining device of an output target which is decoded in the license management information decoding step based on the first receiver ID of the content obtaining device of the output target; 
 an authorization status determining step for determining whether or not the content obtaining device is allowed to display the content based on the authorization information obtained in the authorization information obtaining step; 
 a lock control information obtaining step for obtaining lock control information associated with a second receiver ID for controlling a lock status which is either a status where the output of the license information to the content obtaining device is allowed or a status where the output of the license information to the content obtaining device is prohibited, the second receiver ID identifying a larger number of the content obtaining devices than the first receiver ID; 
 a lock control process step for controlling the lock status based on the lock control information obtained in the lock control information; and 
 a license information output step for outputting the license information to the content obtaining device of the output target if the content obtaining device of the output target is determined to be allowed to display the content in the authorization status determining step and the lock status is the status where the output of the scramble key is allowed. 
 
     
     
       20. A computer readable non-transitory recording medium which stores a license information management program for managing an output of license information for displaying a content to a content obtaining device which receives and displays the content, the program causing a computer to function as:
 a license management information decoding device for decoding license management information in which individual authorization information is encrypted, the individual authorization information including authorization information for a plurality of the content obtaining devices, wherein the authorization information for the plurality of the content obtaining devices includes a sequence of bits, wherein each bit is associated with a single one of the plurality of the content obtaining devices and the bits are arranged in a numerical order of contend obtaining device IDs of the plurality of the content obtaining devices to indicate presence or absence of authorization for each of the plurality of the content obtaining devices to display the content; 
 an authorization information obtaining device for obtaining the authorization information for the content obtaining device of an output target which is decoded in the license management information decoding step based on the first receiver ID of the content obtaining device of the output target; 
 a lock control information obtaining device for obtaining lock control information associated with a second receiver ID for controlling a lock status which is either a status where the output of the license information to the content obtaining device is allowed or a status where the output of the license information to the content obtaining device is prohibited, the second receiver ID identifying a larger number of the content obtaining devices than the first receiver ID; 
 a lock control device for controlling the lock status based on the lock control information; and 
 an authorization status determining device for determining whether or not the content obtaining device is authorized to display the content based on the authorization information obtained by the authorization information obtaining device and outputting the license information to the content obtaining device of the output target if the content obtaining device is authorized to display the content and the lock status is the status where the output of the license information is allowed.